JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.. Wiley and Nordic Society Oikos are collaborating with JSTOR to digitize, preserve and extend access to Ornis Scandinavica. P. 1993. Determinate laying and egg attendance in Common Eiders. -Ornis Scand. 24: 48-52.Egg laying, egg attendance by females, and egg loss were studied in the Common Eider Somateria mollissima. Clutch size fixation appeared to occur before the first egg was laid (determinate laying). Intervals between the laying of eggs were usually about 24 h. Permanent egg attendance started before clutch completion (4 to 6 eggs), usually from the second egg on, and was independent of the actual number of eggs in the nest and final clutch size. Egg loss during inattentive periods was 80 times higher than during attendance. Spontaneous breaks in incubation occurred at intervals of 1-3 days, but sometimes a female left 2 or 3 times a day. Breaks were used for drinking and lasted between a few min and 2.5 h. Females left most frequently in the first few hours after sunset. The ducklings hatched nearly synchronously except the last egg, which hatched on average 8 h later than the others. Early egg attendance, fasting during incubation, and leaves during night hours will have evolved for clutch protection.
The biomass of the benthic macrofauna of the tidal flats of the Banc d'Arguin, Mauritania, retained by a sieve of 0 .6 mm, has been estimated . The total biomass amounts to about 17 .0 g ash-free dry weight (AFDW) m -2 in the area sampled (about 300 km 2 ). The large bivalve Anadara senilis is responsible for 8.1 g AFDW m -2, over 100 other species for another 8 .9 g m -2 . The largest biomasses are found near the continental shore ; at the offshore tidal flats benthic filter-feeders are lacking . Seagrass beds, which occupy the larger part of the tidal flats, have an under average biomass . Sebkhas, extremely saline flats above mean high-water mark, contain no live animals . To sustain the consumption of benthic prey by the very abundant wintering shorebirds relatively low P/B ratios are sufficient .
151
Toxic and biochemical effects of 3,3',4,4'-tetrachlorobiphenyl (CB-77) and Clophen A50 on eider ducklings (Somateria mollissima) in a semi-field experiment. Murk, A.J.; van den Berg, J.H.H.; Fellinger, M.; Rozemeijer, M.J.C.; Swennen, C.; Duiven, P.; Boon, J.P.; Koeman, J.H.
General rightsIt is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons).
Disclaimer/Complaints regulationsIf you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: http://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.